Which statement differentiates cystitis from pyelonephritis?

• A. Cystitis is a bladder infection with dysuria and frequency; pyelonephritis is a kidney infection with flank pain, fever, CVA tenderness
• B. Cystitis presents with flank pain; Pyelonephritis presents with dysuria
• C. Cystitis is more likely to be complicated by fever; Pyelonephritis has no systemic symptoms
• D. Cystitis occurs only in children; Pyelonephritis occurs only in adults

Answer: (A)

The main idea is where the infection is located and how that affects the usual symptoms. Cystitis is a bladder infection, so it presents with irritative urinary symptoms like dysuria (painful urination) and increased urinary frequency or urgency. Pyelonephritis is a kidney infection, and it tends to cause more systemic and renal-specific signs: flank or groin pain, fever, and costovertebral angle tenderness when the kidney area is tapped.

This makes the statement that cystitis is a bladder infection with dysuria and frequency and that pyelonephritis is a kidney infection with flank pain, fever, and CVA tenderness the best choice because it matches the typical clinical patterns for each condition. The other options mix up where the symptoms originate or emphasize signs that are not as characteristic for one condition (for example, flank pain being linked to cystitis, or fever not usually present with uncomplicated cystitis).